Allow me to offer you an idea:
When I go to Yelp to search for a restaurant, the filters I have available are type of restaurant, proximity, rating and price. My next step is to either sort by those filters, or individually click a restaurant. Looking at an individual restaurant, my options for consideration are photos of the restaurant, consisting of either interior/exterior or images of the food, and user reviews. The user reviews consist of reviews about the service, atmosphere and food, but I have to chug through each review to get this type of specific information. And with a task of choosing a restaurant and having to repeat these sets of actions is immensely tedious.
What's missing?
A way to discover restaurants near me that I can discover by their actual dishes. The user flow would be this -> I'm in the mood for a burger. Show me restaurants that serve burgers. I get a range of places from diners to more high-end to delis and more, but instead if getting a list of joints, I get a sortable grid of user's burger photos from places near me. Then, all I need to do is say, that burger is the one I want and, barring other misc info such as price or needing reservations and what not, I will go there and get the burger that I saw with my own eyes.
The advantage you will have over Yelp is that While Yelp provides a way to discover restaurants by very general filters, you will provide a way to directly discover restaurants by the actual individual dishes.
As a side note, think about when you go to a restaurant and get a menu that has pictures. It gives so much more reference to choosing a dish, because the mystery is taken out of the equation. Your service would do exactly this. Remove the mystery of what you're going to a restaurant for.
Also, while you can see some food items on Yelp in the individual restaurant pages, #1 they come with no context and #2 I can only access these photos on these individual pages which is tedious.
There you have it.